CH633401A5 - Receiver for receiving an traegerwelle. - Google Patents

Description

633401 2

PATENT CLAIMS The invention has for its object to provide a compatible

1. Receiver for receiving a carrier wave, which is amplitude-modulated with len AM stereo receivers of the type of signal information mentioned at the outset, to create the proportional, which, with a particularly simple structure, is particular to the sum of a first information signal A and the like has favorable tuning properties.

is a second information signal B, the carrier wave 5 serving to solve this problem, which is furthermore phase-modulated in claim 1 with a signal which features stored, where with Ci and Cz usual constants are proportional to an angle Ò which is the shape <D = arc tg ten and are generally designated with A and B signals. (Ci (A - B) / (C2 + A + B) where Ci and C2 are constants, according to a particularly preferred embodiment where the receiver has an input stage (11, 12) around the subject of the invention it is provided that the received Receive signal and derive an intermediate frequency 10 gene transmission signal in a conventional manner in an RF signal, and wherein an envelope demodulator (13) and an IF stage is processed, after which the sum is connected to the input stage to the Amplitude module signal is demodulated in an envelope demodulator and lation to demodulate on the intermediate frequency signal is supplied to a matrix.

characterized in that the receiver is synchronous. The invention is described below, for example, with reference to the detector circuit (16), which is described with the input stage 15 drawing; in this the only figure shows one connected to provide an output signal which is proportional to (A block diagram of a receiver in which the invention - B) cos ® that the receiver continues to be used. Instead of the signals A and B in the execution correction circuit (17,22,23,25) is shown, which with the example of the input to the left and right channel L and R reference stage and connected to the synchronous detector circuit.

in order to provide an output signal which is proportional to A - B. The receiver shown in the drawing is functional and that the receiver furthermore determines a matrix, has a compatible AM stereo signal from a transmitter, to process signals A - B and A + B so as to record as separate output signals A and B are provided in U.S. Patent Application 674,703. is described. A transmission signal from a transmitter according to

2. Receiver according to claim 1, that the input stage is one of the above patent application with currently pre-RF stage and an IF stage. 25 existing monophone receivers compatible in the way

3. Receiver according to claim 1, characterized in that the correction that the carrier with a monophonic signal amplitude circuit has a limiter circuit (17) and is dulated, namely according to the expression (1 + L + R), circuit (22) has to provide a signal which is contained in one with the so that the entire stereo information in the phase modulation phase of the non-modulated intermediate frequency signal. In short, the carrier will be related to the sum determined, and further has a cosine phase 30 (L + R) and the difference (L - R) in a 90 degree phase shift detector (23), which has the limiter switching is modulated so that the amplitude change elimation (17) is connected and is kidneyed with the signal generating circuit and only the phase change remains. This is followed by (22) in order to provide a signal which is cos ® proportional, an amplitude modulation with 1 + L + R in a corresponding and finally a circuit (25) which serves to provide the modulator with a high level . The output signal output signal of the synchronous detector (16) by the output or transmission signal is then divided into (1 + L + R) cos (wct output signal of the cosine phase detector (23). + Arc tg [(L - R) / (1 + L + R)] It should be noted that «L» are used in the present description only as an example.

In the receiver, the antenna 10 receives a compatible 40 A stereo signal of the form specified above, and this amplitude of the ZF stage 12 processed. The monophonic signal or that is modulated. Sum signal L + R is achieved in that the output

A number of arrangements are known which will connect an AM stereo transmission connected to the IF stage to an envelope demodulator 13 and a corresponding reception. The signal L + R is then supplied to a matrix 14. One of these arrangements is compatible in the way it performs. A detector or demodulator 15 with automatic that the envelope of the transmitted signal can only contain the sum of the gain control between the output of the envelope or the monophonic information (A + B) and the curve demodulator 13 and the IF stage 12 in a total stereo information by phase modulation of the feedback are arranged to transmit the gain of the IF stage in gers. To control this arrangement including transmitter 50 in a manner known per se. The output of the IF stage and receiver is connected to the dulator 16 in US patent application No. 674 703 (corresponding to 12 is also with a synchronous detector or synchronous demo-speaking German patent application P 27 15 741.1-35) and to a limiter stage 17 . The patent owner described. In this description, all limiter stage 17 is connected to a phase detector 18, embodiments of the stereo receiver for demodulation are further described with a low-pass filter 19 and with a voltage-compatible signal, which is controlled by an oscillator. This circuit stage has a pha-This means that signals with a phase shift senstere feedback loop 22, from which an output signal of 90 degrees are supplied, which is then fed to the synchronous detector 16 in a synchronous (sin wct). A detector or synchronous demodulator to be demodulated in order to provide a signal of the limiter stage 17, which contains only the transmitted sum signal and the difference signal and finally A phase information, is a cosine phase and B. While all the embodiments described in the above-mentioned patent detector 60 as an output signal (cos wct) of the phase-rigid avoidance, practical feedback loops 22 are supplied. The cosine phase detector 23 are in the form of a guide, but can still be a receiver, which is a multiplier stage, which for example uses the type Motorola synchronous detectors or synchronous demodulators MC 15 95 and is a four-quadrant multiplier. det, both in the sum channel and in the difference. The instantaneous phase difference between the two carrier fre channels are difficult to adjust because the beats 65 frequency (unmodulated and transmitted) is in the cosine phase during the tuning process from the low frequency channels. Transmitter detector 23 is scanned and represents the proper len to be kept away and other tuning information that is necessary to make the original. Restore stereo signals. The desired correction

3 633401

information is a signal which is the cosine of O or if the phase-locked feedback loop is locked to wct,

the cos arc tg [(L-R) / (l + L + R)] or (l + L + R) / y (1 + L is the DC voltage level of the cosine phase detector 23

+ R) 2 + (L - R) 2 is proportional. If the desired correction at the output after filtering the filter 27 is supplied with sufficient correction information of a divider stage 25, which also gets high in order to get the mono / stereo switch 28 into the stereophonic output signal of the synchronous detector 16, 5 operating mode will be switched. This enables the signal to be fed to the output signal of the divider stage to L-R, the desired L-R of the matrix 14, which have L + R at their

Stereo difference signal. Output brackets supplies separately.

Until the receiver is properly tuned, it must be noted with regard to the signal that the

however, the output signal of the phase-locked feedback loop signal of the IF stage 12 the expression (1 + L + R) cos (wct

22 not a function of wct, but a frequency which is proportional to io + ®), whereby the following relationship applies: ® = wct approaches when a transmission signal is tuned in. arc tg [(L-R) / (1 + L + R)]. The output signal of the envelope-The difference frequency would then in the correction signal at the ven demodulator 13 becomes proportional ztuj-, + R. The output of the cosine phase detector 23 occurs and an output signal of the limiter stage 17 is proportional to cos cause unwanted output signal in the differential channel. (wct + O), and the output signals of the rigid

Therefore, the output of the cosine phase detector 15 will be proportional to sin wct and after a guide loop

23 connected to a low pass filter 27 (2-10 Hz), in which phase shift also proportional to cos wct. The off-the average DC voltage level of the output signal of the synchronous detector 16 is the product of signais can be used to create a mono / stereo (1 + L + R) cos (wct + ®) and sin wct. Neglecting to control switching device 28. Switch 28 is one of the dual frequency 2 wct and under back-voltage controlled switches and is set to switch 20 to account for the fact that ® = arc tg [(L - R) / (1 + L + R) ] remains in the monophonic position until the phase is reversed, it should be obvious that the product locks in proportion to the leading loop on wct; then the switchover to (L - R) cos O ist. The output signal of the cosine phase end-a stereophonic position. tector 23 becomes proportional to cos <D, and the output signal

In monophonic operation, only L + R of the divider 25 assigned to the matrix is thus proportional to (L - R) cos «5 / cos <D

leads, and the recipient is tuned, using only this 25 or (L - R). With the input signals (L + R) and (L - R)

monophonic low frequency output signal is used. produces the matrix 14 output signals L and R.

When the recipient is attuned or tuned and

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1 sheet of drawings